A conventional socket adapter design, as shown in FIG. 1, has two receptacles 111 at proper points within an insert holder 11, and which are provided for copper tabs 21 at ends of a power cable 20 to a power source. The receptacles 111 are separated by a partition 112. The insert holder 11 has pinholes 113 arranged on its front side and there are two passages provided for cords going behind them. The copper tabs 21 of the power cable 20 are placed in position in the insert holder 11, while leaf copper conductors 33 are inserted in recesses 114 arranged in the insert holder 11. Meanwhile, fuses 80 are placed in the receptacles 111, then the insert holder assembly is inserted into the housing 12 to form a socket adapter. However, such a socket adapter design has some shortcomings, such as poor waterproof performance, owing to the fact that here are gaps between the insert holder 11 and the housing 12 and between the cover 13 and the housing 12. Further, if joints 22 of the power cable 20 with the copper tabs 21 are in a poor condition, potential risks of removal of cord(s) and a short circuit will incur Furthermore, the cover 13 is not able to provide a positive waterproof performance. Because there is not any protection at the joints 22 of the power cable 20, power failure or electrical leakage will be encountered due to cord removal or loosing after long periods of use or under an eventual foreign force. Therefore, it is really not an ideal design.
So, a socket adapter design which is able to provide a waterproof function, secure connection, shock resistance and high safety is needed.